The geocaching.com website is undergoing some cosmetic changes at the moment, breaking most of the Greasemonkey scripts which have sprung up to correct its deficiencies. I wrote one which inserted links to various mapping services, which needed some TLC after they dropped OS grid references from UK cache pages.
Fortunately, thanks to the geotools javascript library which I had a hand in creating, you can perform a reasonable WGS84 to OSGB conversion entirely on the client side.
So, within a few hours of the geocaching.com developers “breaking” their site, myself and others went and fixed it again with the wonder of Greasemonkey. You can find my script for inserting map links here.